Astronomers have been analysing light signals from 2.5 million
stars observed by the Sloan Digital Sky Survey, and have detected
strange 'strobe-like' bursts coming from not one, but 234 stars.

The pair went so far as to suggest that these light pulses "have
exactly the shape of an Extra-Terrestrial Intelligence signal",
and now Stephen Hawking's alien-hunting mission is on the case to
confirm or disprove these claims.

Let's be clear right off the bat — the claim by astronomers
Ermanno Borra and Eric Trottier from Laval University in Canada
that 234 extra-terrestrial civilisations might be beaming a
coordinated light signal towards Earth based on anomalies in the
data is extremely premature.

It's also pretty irresponsible to be throwing the possibility of
"Aliens!" around, given the fact that the paper has yet to be
formally peer-reviewed, and replication of the results has not
been attempted by an independent research team.

It's also worth noting that researchers from the Breakthrough Listen project — funded by
Stephen Hawking and Russian billionaire Yuri Milner, and run by
the SETI (Search for Extraterrestrial Intelligence) Research
Centre at the University of California Berkeley — say aliens are
about the last thing they expect to find when they investigate
these claims.

But when the Universe — or let's be honest, human error — serves
up something intriguing, it's almost always worth a second look.

"However, extraordinary claims require extraordinary evidence. It
is too early to unequivocally attribute these purported signals
to the activities of extraterrestrial civilisations."

So let's run through what Borra and Trottier have actually found.

A "preferred result?"

Things start off a little wobbly, because as Shannon Hall explains for New
Scientist, Borra had hypothesised back in 2012 that if
an extraterrestrial civilisation wanted to contact us, it would
make sense to beam laser pulses at us that look unnatural enough
to warrant investigation.

He said the kind of energy required to blast such a signal
towards Earth from elsewhere in the galaxy "is not crazy", so he teamed up with Trottier
to pore over the 2.5 million stars recorded by the Sloan Digital
Sky Survey to see if any of them have produced such a signal.

Several
antennas that are part of the Allen Telescope
Array.SETI
Institute

And there's our first warning signal — a good scientist knows not
to approach data with a preferred result or preconceived notion
in mind, because that can introduce bias, and the scientist could
subconsciously (or otherwise) ignore information that goes
against that.

The
pair reports that they detected the exact type of signal they
had been looking for in some 234 stars.

As Hall explains for New Scientist,
if you take the aliens out of it, what they found was that the
overwhelming majority of the 2.5 million stars are in the same
spectral class as our Sun, but 234 of them are beaming pulses of
the same periodicity — roughly 1.65 picoseconds — towards Earth.

Could it be human or software error in data calibration or
analysis? Absolutely, and the pair's conclusions have — not
surprisingly — been met with a whole lot of criticism in the
scientific community.

How to verify

"There is perhaps no bolder claim that one could make in
observational astrophysics than the discovery of intelligent life
beyond the Earth," director of the SETI Research Centre at
Berkeley, Andrew Siemion, told Hall.

The Atacama Large
Millimeter/submillimeter Array (ALMA) in Chile, with the stars of
the Milky Way galaxy in the background.ESO/B. Tafreshi
(twanight.org)

"It's an incredibly profound subject — and of course that's why
many of us devote our lives to the field and put so much energy
into trying to answer these questions. But you can't make such
definitive statements about detections unless you've exhausted
every possible means of follow-up."

That's why the SETI Research Centre and the Breakthrough Listen
project have decided to get involved — they want to know what's
really going on here.

They explain that we already have internationally
agreed-upon protocols if you want to find evidence of advanced
life beyond Earth, which include independent verification using
two or more telescopes, and "careful work" to determine false
positive rates and rule out all other explanations.

They've also established a 0 to 10 scale for quantifying
detections of phenomena that may indicate the existence of
advanced life beyond the Earth called the Rio Scale.

They say the Borra-Trottier result is currently a 0 or 1
("None/Insignificant") on this scale, but they're still
determined to get to the bottom of things.

"The Berkeley SETI Research Centre team has added several stars
from the Borra and Trottier sample to the Breakthrough Listen
observing queue on the 2.4-metre Automated Planet Finder (APF)
optical telescope," they announced last week.

"The capabilities of the APF spectrograph are well matched to
those of the original detection, and these independent follow-up
observations will enable us to verify or refute the reported
detections."

We'll have to wait and see what they find, but let's all be glad
that if someone wants to throw claims of aliens around, they'd
better be ready to answer to the SETI researchers first.